This November I’ll be taking an extended trip to Belize for my honeymoon. Yes, you’re allowed to be very jealous. While there, we’re planning on taking a hike through some Mayan ruins, which is something I’ve always wanted to do. Besides the impressive feats of archaeology, the ancient temples hold amazing pieces of art depicting the history of the fallen civilization. Who knows, maybe I’ll even get interested in the history and learn a little bit about the rise and fall of the often over-romanticized central americans.

Going into their history isn’t as straightforward as one might think, however. The problem comes with the way the Aztecs kept their calendar for a long time. Before the Europeans arrived and decimated their populations, the Mayans used what is called the Long Count calendar.

That calendar is pretty interesting in and of itself. It’s almost based on a 20-count system that uses five placeholders to count the days. Allow me to explain a bit more by using some examples.

Take the following sequence of 0.0.0.1.5. Just like our 10-based counting system, the last digit is simply itself. But unlike our counting system, the second to last number jumps by 20s. So the digit I just spelled out is 25 instead of 15. And if we change it to read 0.0.0.3.7, we get 67.

Getting the hang of it yet?

Here’s one more curve. The third to last digit is not based on 20s. Instead, it’s based on 18s. So 0.0.2.0.0 is equal to 360 instead of 400. I know that’s a bit confusing, but those Mayans were crazy folks.

Anyways, moving on, I mentioned that studying Mayan history is a bit difficult, and that’s not because their counting system was different from ours. It’s due to another line that you might have caught me mention earlier.

The calendar fell into disuse before the Europeans arrived.

Think about that for a second. You can look at a historical document and see the years in which events happened. But if you don’t know when the calendar started counting, the information is pretty useless. And if the calendar only depicts events that happened before you were around to see them, figuring out the dates of events becomes pretty tricky.

For the past 100 years or so, scientists have been debating exactly how the Long Count calendar matches up with our own historical record. Now, thanks to some fancy dating tricks used by researchers at Penn State, the debate has finally been settled.

The study took samples from an elaborate carving on the ceiling of a temple in the ancient Maya city of Tikal, Guatemala, that carries a dedication data in the Maya calendar. To analyze when the piece of wood was carved, they turned to two elements – carbon and calcium.

First they did some carbon dating. As you may know, there is a known amount of carbon-14 in the atmosphere. Your typical carbon comes in the form of six protons and six neutrons, but this uncommon isotope has two extra neutrons making it heavier than normal. Because we know how long it takes to decay and can measure how much of it is in an organic sample, we can estimate the age of a sample.

There are a few caveats, however. The amount of carbon-14 in the atmosphere is not constant, and therefor estimates of past concentrations could be off. Also, the relative amount in the northern hemisphere is different from the southern, and the tree that this Mayan carving was made from sits right on the border of wind currents from both.

The place they found the carving that was analyzed.

So to back up their carbon dating tests, the researchers looked at the amount of calcium in different layers of the wood. While levels of carbon-14 might not be quite as stable and predictable as we’d like them, the seasons most certainly are. During the rainy season that most any traveler knows to avoid when booking vacations to the region, trees and other plants take up a lot more calcium than during the dry season. By carefully counting the number of peaks and valleys of calcium content across the piece of wood, the researchers were able to verify their carbon dating technique. It’s sort of like counting rings on a tree, except that these trees don’t have visible rings. I knew you were wondering why they didn’t just use their damn eyes.

But in any event, after all that work, the answer was rather mundane.

It turns out that this particular carving was made between the years of 695 and 712 AD. Matching the events and dates recorded in the engravings to other known calendars indicates that the original, standard estimate of how our calendars align is actually correct. Back in 1905, Joseph Goodman put forth the Goodman-Martinez-Thompson hypothesis of how the Long Count calendar correlates to our own.

And he was right all along.

So there you go. Now we know that Jasaw Chan K’awiil’s accession to Tikal’s throne occurred in AD 682 and that his decisive victory over Calakmul occurred in AD 695. You’re riveted, I know.

But what’s also cool and interesting is that we can place a date on when the calendar began and when the Mayans believe the world was first created. The date 0.0.0.0.0 correlates with August 11, 3114 BCE. Take that, creationists. The world is actually 5,000 years old, not 6,500 – 10,000 years old.

Also, a host of people from other universities, because you know, this shit is hard. Other researchers were Irka Hajdas and Gerald H. Haug, Swiss Federal Institute of Technology; Simon Martin, University of Pennsylvania Museum; Hector Neff, California State University Long Beach; Jaime Awe, Institute of Archaeology, Belize; David L. Lentz, University of Cincinnati; Flavio S. Anselmetti, University of Bern; Mark Robinson, Louisiana State University; Norbert Marwan, Potsdam Institute for Climate Impact Research, Germany; John Southon, University of California Irvine; and David A. Hodell, University of Cambridge, UK.